We use 3 types of mount board, think ‘Good’ Better’ and ‘Best’.
‘Good’ mount board has a surface, core and backing paper which is buffered with calcium carbonate to an alkaline reserve of 3 -5%, pH7.7 - 8.5, it has high bleed and fade resistant decorative facing papers. We use this for the majority of our framing and have done for 20 odd years, so it has a good track record with us.
‘Better’ mount board is made from 100% alpha cellulose and is conservation quality.
It is lignin free, which means that the part bad part of the wood pulp has been removed. It too is buffered with calcium carbonate to an alkaline reserve of 3 - 5%, pH 8.0 - 8.5, and is high bleed and fade resistant.
Ageing resistant complying with ISO 9706.
‘Best’ mount board is 100% premium cotton board, so not wood pulp. It has a solid colour so the bevel is the same colour as the top paper.
Being cotton it is 100% lignin free and speck free, again buffered with calcium carbonate and this time to an alkaline reserve of 3 - 5%, pH 8.5 - 9.5.
It can also be supplied unbuffered which is useful for framing valuable photographs.